Most patients with type 1 diabetes (T1DM) and reduced eGFR have classic glomerular changes of DN regardless anti-PD-1 antibody of albuminuria status. Typical renal structural changes of DN are usually also observed in patients with T2DM, reduced eGFR and albuminuria. However, predominantly interstitial, tubular or vascular damage or near normal renal structure have also been reported in biopsies obtained from patients with T2DM, regardless of eGFR or albuminuria status, in the absence of any other known cause for renal dysfunction. Despite the above, in people with diabetes and proteinuria, non-diabetic kidney disease (NDKD) alone or superimposed on DN changes
is not an uncommon finding. It is important that NDKD is diagnosed. Despite the attention to strict metabolic control and blockade of the renin–angiotensin-aldosterone system,
proteinuric DKD is usually progressive, whereas NDKD is potentially treatable, depending on aetiology. Therefore, we have briefly reviewed the contemporary spectrum of DKD, the histology and clinical predictors of NDKD and present several clinical vignettes (Box 1) to illustrate the variability of renal disease in diabetic patients that have presented to one of our hospitals. Case 1. DKD in T1DM A 47-year-old man was diagnosed with T1DM since childhood, find more with multiple complications including proliferative retinopathy, peripheral neuropathy and cerebrovascular disease. Other medical history included obesity and hypertension; there was no family history of renal disease. He presented with worsening nephrotic-range proteinuria (24 h urinary protein 6.5 g) and rapid deterioration in renal function; HbA1C was 9.8%. Renal biopsy confirmed Class IV DN (Fig. 1). Case 2. DKD in T2DM A 38-year-old obese woman presented with rapid weight gain (12 kg in one week) associated with bilateral oedema to her upper thighs. She had significant proteinuria (urinary protein/creatinine Fludarabine cell line ratio 378 mg/mol) with impaired renal function (serum creatinine 122 μmol/L). Past history was notable for gestational diabetes. She was diagnosed with T2DM (HbA1c 13.4%) and renal biopsy confirmed Class III DN with nodular glomerulosclerosis
(Fig. 2). Case 3. FSGS causing nephrotic syndrome A 43-year-old obese woman with 11 year history of T2DM, presented with nephrotic syndrome (gross peripheral oedema, urinary protein/creatinine 913 mg/mol, serum albumin 26 g/L) and preserved renal function (eGFR 77 mL/min). Her HbA1c was 7% with no known diabetic complications. Renal biopsy demonstrated FSGS with mild chronic tubulointerstitial damage (Fig. 4). Case 4. Hypertensive kidney disease A 74-year-old man with T2DM for 7 years was referred with gradually worsening renal impairment (eGFR 21 mL/min). His HbA1C was 6.3% on oral agents with no vascular complications. Other medical history included hypertension and obstructive sleep apnoea. Urine sediment did not show any proteinuria; kidneys were small-sized on ultrasonography.